PLB 445 and Zoology 585D Wetland Ecology and Management

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PLB 445 and Zoology 585DWetland Ecology and
Management
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Why study wetland ecology?

• Why not cover wetland ecology in limnology or a
  terrestrial ecology course?
• wetlands are transitional between aquatic and
  terrestrial systems
• wetlands are ecotones in the landscape
• duration/frequency of flooding varies spatially
  and temporally
• difficult to classify/delineate boundaries

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What is a wetland?

• kidneys of the landscape
• 3 main features
• presence of water
• unique soil conditions develop
• presence of vegetation adapted to wet conditions
• highly productive
• estimated 6 of the lands surface

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Major Wetland Types

• swamp
• marsh
• bog
• fen

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Swamp

• dominated by woody plants
• river floodplains or big depressions

Bottomland hardwood swamp
Mangrove swamp
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Marsh

• high flooding frequency
• herbaceous vegetation
• freshwater or salt marsh

Vernal pool
Salt marsh
Prairie potholes
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Bog

• spongy, peat deposits (store Carbon)
• low nutrients
• precipitation is main water source

Northern bog
Pocosin
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Fen

• peat-forming wetland
• water from runoff, groundwater, and streams
• higher in nutrients than bogs

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Storage of floodwaters
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Habitat for Species
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Filtration/Transforming

• uptake of excess nutrients
• filters contaminants
• soil retention

Riparian forest buffers stream
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Wetlands as Buffers
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Organic Export to Downstream Communities
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Coastline Protection

• Hurricane Lili (2002) in Southeast Louisiana

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Carbon Cycling

• carbon storage
• climate regulation
• much of fossil fuels used today produced during
  Carboniferous Period 280-345 million years ago
• modern peatlands are huge carbon sink (production
  gt decomposition)
• estimated 500 billion metric tons of C released
  if peatlands destroyed

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Human Use

• some human civilizations long associated with
  floodplains
• Marsh Arabs of Iraq
• Cajuns of south LA
• peat harvesting
• rice paddies

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Heritage
Coastal Louisiana
Kakadu National Park Northern Territory, Australia
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Goods, Services Values of Wetlands

• flood storage
• water quality
• groundwater recharge
• biogeochemical cycles
• sediment stabilization
• pollutant retention
• high productivity

• habitat for many species
• recreation
• economic
• heritage
• protect coastline
• nursery for fisheries
• climate regulation

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Estimated Economic Values of Wetlands (per
hectare) Costanza et al. 1997
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Early Perspectives of Wetlands

• fear and superstition
• Reflected in names (e.g., Great Dismal Swamp)
• Disease
• yellow fever
• malaria
• West Nile
• fertile lands but need improvement
• clearing draining
• Swamp Thing character has changed along with our
  attitudes about wetlands

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Clearing and Draining of Wetlands

• Fertile lands drained and converted to
  agriculture
• Swamp Land Act in 1849 control floods in
  Mississippi River Basin and use for more
  beneficial purposes
• Extended to other states in 1860
• Result huge losses of wetlands in US
• Conversion to agriculture top reason

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Causes of Wetland Loss Degradation

• conversion to agriculture
• hydrologic modifications
• urbanization
• peat mining
• pollution

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Habitat Loss
ex - Lower Mississippi River Basin

• conversion to agriculture
• recent urbanization
• fragmentation
• remaining patches too small to support some
  species

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Conversion to Agriculture
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Extinct fauna - Floodplain Forests
Carolina parakeet
?
Ivory-billed woodpecker
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Threatened Endangered Fauna
Florida Panther
Louisiana Black Bear
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Urbanization

• ex - San Francisco Bay

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Hydrologic Modification

• ex - Kissimmee River in Florida

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Peat Mining

• loss of habitat
• Carbon sinks become Carbon sources
• implications for global climate change

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Pollution
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Global Trends

• Trends in US not different from global trends
• Approximately 50 of wetlands have been lost

Mitsch 1998
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Conservation and Restoration

• Prompted by tremendous losses
• Much interest in wetland science
• Wetland scientists must be a jack of all trades
• Hydrology
• Soils
• Vegetation
• Ecology
• Chemistry
• Landscape ecology
• Policy, legislation
• Engineering

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Wetland Definitions

• Most have 3 features in common
• Presence of water (at surface or within rooting
  zone)
• Unique soil conditions soils develop under
  anoxic conditions (without oxygen)
• Have vegetation or will support hydrophytic
  vegetation - adapted to wetland conditions
• intolerant species absent

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Wetland Definitions
Hydrology (water level, frequency, duration)
Geomorphology
Climate
Biota (plants, animals)
Physiochemical (soil, chemistry)
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What is controversial about wetlands?Why are
definitions challenging?
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Hydrology

• Most controversial
• Depth and duration of flooding
• Varies spatially and temporally

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Wetlands as Ecotones

• Transitional
• Can they be lumped in with aquatic
• Some say they have unique properties

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Species that occupy Wetlands

• Facultative can live in wetland or in drier
  conditions
• Obligate restricted to the wetland
• USDA Plants database

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Wetlands vary in size

• Small,isolated wetlands such as Carolina bays
• Huge, expansive peatlands
• Affects function and how we conserve them

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Location

• Coastal influenced by salinity pulses, tides,
  hurricanes
• Floodplains influenced by river
• Isolated depressional area immediately
  surrounding it

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Condition

• Disturbance
• Natural
• Anthropogenic
• If hydrology modified, difficult to define the
  wetland

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Gradient or Discrete Boundaries?
terrestrial
wetland
aquatic
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Scientific Definitions

• USFWS 1956 Circular 39 definition
• Lowlands covered with shallow and sometimes
  temporary waters
• Shallow lakes and ponds with emergent vegetation
  are included but deep or permanently inundated
  water bodies are not
• USFWS 1979
• Lands transitional between terrestrial and
  aquatic systems
• Water at or near surface or covered by shallow
  water
• Must have 1 or more of the following
• Supports hydrophytic vegetation
• Hydric soil undrained
• Substrate is non-soil (peat) saturated with water
  or covered by shallow water at some time during
  growing season
• Key points hydric soils and hydrophytes
• Used more for scientific studies, difficult to
  employ for regulation

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Scientific Definitions (cont)

• RAMSAR Convention Iran 1971
• does not include soils or vegetation
• extends to areas of marine water
• meant to encompass a wide range
• generally considered too broad

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Legal Definitions

• US Army Corps of Engineers
• legal responsibility for dredge and fill permit
  in Clean Water Act
• Inundated/saturated by water and supports
  vegetation that is typically adapted for life in
  saturated soil conditions
• Must have all 3 components
• NRCS
• Result of Swampbuster Provision, this definition
  included in Food Security Act definition
• Administer wetland protection
• To protect wetlands on land previously exempt due
  to agriculture
• Emphasis on hydric soils
• Excludes wetlands in Alaska, which calls into
  question scientific validity

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Jurisdictional Wetlands

• Ones that fall into the wetland class based on 1
  or 2 of the legal definitions
• Legally defined wetlands